Stan de SD
2009-12-27 22:32:57 UTC
Does anybody here have any answers about the Muni's derailing problems? Why
now, especially after an $8 million fix?
The papers never report any root causes. Either Muni doesn't know ornow, especially after an $8 million fix?
isn't telling. Compare to the reporting on the CTA's recent 'L'
"Investigators determined that the train operator disobeyed a "stop"
signal and caused the derailment by driving the train over a track
switch that was not aligned for the train to pass safely"
(sfgate.com) are any indication, it's clear that nobody in the SF
media (outside perhaps a popular yet cantankerous radio show host on
the call-letter deficient station) has much of a clue how railway
equipment works, much less the inclination to get off their lazy asses
and do some work. Derailments can be related to the track (out of
gauge, too tight curvature, debris in flangeways/frogs/switchpoints),
vehicles (wheel/flange profile, wheelbase length, harmonic vibrations/
oscillations during operation, high center of gravity) or operator
issues (excessive speed, heavy braking in curves). None of this is
really rocket science (your typical nerdy train-buff kid can tell you
more than you ever wanted to know), but the type of old-school
gruntwork and pounding the pavement to get the whole story is likely
too much effort for your typical AP-wire-spoonfed J-school graduate
these days.
Interestingly enough, this member of an older generation remembers a
chronic derailment issue with Amtrak's first generation of new diesel-
electric locomotives (EMD SDP40Fs for you foamer types). This issue
perplexed Amtrak for several years in the 1970's, as this particular
design was a minor modification of the six-axle GM locomotives that
Amtrak's main tenants (UP, BN, ATSF, Conrail) rostered in the
thousands, with negligible problems (in fact, 18 of the Amtrak units
were later sold to the Santa Fe which used them for years without
complaint). The problem was so severe that most of the class were
eventually scrapped while only a few years old, with the prime movers
and electricals re-used for a four-axle variant (F40PH). Years after
the fact, it was noted that the water tanks used for the steam
generator were located relatively high in the carbody, and lacked
proper internal baffling. The hypothesis was that the combination of a
higher than normal center of gravity and centrifugal force of water
sloshing around when the locomotives went into curves at passenger
train speeds resulted in enough momentum to momentarily lift the
locomotive wheels on the inboard side of the curve, causing the
derailments. I would hope that MUNI would have better luck in
resolving such issues in a timely manner, but I have my doubts.